Why do you think people with
these occupations were
chosen to become delegates?

People with those occupations were chosen to be delegates because they were believed to have good negotiation and conveying skills.

Explanation:

The purpose of a delegate is to serve as the bridge between the two or more institutions involved in the engagement. Thus, while choosing delegates, the leaders preferably look towards certain professions that are both knowledgeable and good at negotiation. These professions mostly happen to be that of bureaucrats, businessmen, scholars and academicians, lawyers, etc.